upload
Upload a ZIP file to update an existing Chrome Web Store item draft. Note: Creating new items via API is not supported in v2 — use the Developer Dashboard to create new items.
This record as markdown: /tools/1llum1n4t1-cws-mcp/upload.md
What upload does on Cws
AI agents use upload to create or update resources in Cws, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Cws environment.
| Parameter | Type | Required | Description |
|---|---|---|---|
itemId | string | — | Extension item ID (defaults to CWS_ITEM_ID env var) |
zipPath | string | Yes | Absolute path to the ZIP file to upload |
publisherId | string | — | Publisher ID (defaults to CWS_PUBLISHER_ID env var or 'me') |
Parameters from the server's own tool schema.
Why upload is rated Medium
This tool creates or modifies extension draft data by uploading a ZIP file, which is a reversible change. While the blast radius is significant (an attacker could maliciously modify extension code before publication), it does not permanently delete data or commit irreversible changes, nor does it publish the extension (publish is a separate sibling tool).
From the tool's definition Tool description states "Upload a ZIP file to update an existing Chrome Web Store item draft." The action of uploading and updating a draft is a reversible modification to extension data on the Chrome Web Store.
Attacks that exploit this kind of access
The rule that runs upload safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Cws, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For upload, this is the rule to start with:
upload stays usable, but capped: an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Cws, apply this rule, and every upload call is checked against it from then on.
Questions about upload
Upload a ZIP file to update an existing Chrome Web Store item draft. Note: Creating new items via API is not supported in v2 — use the Developer Dashboard to create new items. It is categorised as a Write tool in the Cws MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
upload accepts 3 parameters: itemId, zipPath, publisherId. Required: zipPath. The full parameter table on this page comes from the server's own tool schema.
Register the Cws MCP server in PolicyLayer and add a rule for upload: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Cws. Nothing to install.
upload is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the upload rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for upload. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
upload is provided by the Cws MCP server (@1llum1n4t1/cws-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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